Antennas are often employed in various wireless applications, such as cellular telephony, global positioning system (GPS) location determination, digital satellite radio reception, and digital video broadcast (DVB) reception. It is generally desirable to reduce the size of antennas and their associated devices.
An antenna's size may be dictated by various operational characteristics, such as its operating frequencies, its specified signal quality requirements, and so forth. For example, an antenna's size typically increases as its operating frequencies decrease.
One technique for reducing the height of antenna devices involves the employment of “top loading” techniques. Such techniques place a load at an end of an element (e.g., a monopole) to make the element appear “electrically taller.” Thus, top loading allows a shorter antenna to operate at a given frequency range.
Many conventional top loading techniques involve the use of relatively large top loads. Examples of such conventional top loads include circular or rectangular flat plates positioned at the top of an antenna device. Such conventional top loads may unfortunately occupy large footprints and block wireless signals being received and/or transmitted by nearby devices.